[REGRESSION] Dell Latitude 7390 Intel UHD Graphics 620 display becomes extremely dim after kernel 7.x upgrade

Hello,

I would like to report a possible kernel regression affecting the
internal display brightness on my Dell Latitude 7390.

After upgrading from Linux kernel 6.14.x to Linux kernel 7.x, the
internal display becomes extremely dim immediately after boot.

Hardware:
Dell Latitude 7390
CPU: Intel Core i7-8650U
GPU: Intel UHD Graphics 620
Driver: i915

Working kernel:
6.14.0-29-generic

Problematic kernel:
7.x

The issue happens on Ubuntu 24.04.4 LTS and Linux Mint 22.2.

Booting back into kernel 6.14 restores normal brightness.

This appears to be a regression between kernel 6.14 and 7.x, possibly
related to Intel i915 backlight handling.

I can provide logs if needed.

Thank you.